Strength development of RHA concrete subject to different curing conditions | |
| Author | Shahid, Mohammad Ali |
| Call Number | AIT Thesis no. ST-85-25 |
| Subject(s) | Concrete--Testing Concrete--Curing |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | This study was aimed at investigating the effects of curing conditions on the mechanical properties of rice husk ash (RHA) concrete as compared to normal concrete. The types of curing included air-dry, fog-room, use of membrane sealing compound, under water at elevated temperature, atmospheric and high pressure steam curing. Two mix proportions of concrete having medium and low strength were considered. The percentage of RHA replacement was kept constant at 40% by weight throughout. The mechanical properties obtained were the compressive and tensile strengths at 3,7,14 and 28 days and the secant modulus of elasticity at 40% of the ultimate strength. In addition the behavior of RHA and normal concrete subjected to hot air heating and curing at very low temperature was also investigated. Test results reveal that at normal curing temperatures the early strength development of RHA concrete is lower than that of OPC concrete. However at later ages strengths comparable to those of OPC concrete are obtained. RHA concrete when cured under water at elevated temperature or when subjected to steam curing processes at high temperature develops higher strengths especially at early ages than OPC concrete. However at the age of 28 days the margin becomes insignificant. Like OPC concrete, RHA concrete has the potential of achieving high early strengths at the very early ages if the curing temperature is substantially raised when the concrete is still fresh. On the other hand the rate of strength development of RHA concrete is significantly retarded at the early ages if cured under very low temperature. Air-Drying of both RHA and OPC concrete is found to be insufficient and the strengths obtained are lower than the normal fog room curing, whereas the use of sealing compounds do not affect the rate of strength development of RHA concrete and the strengths obtained at different ages are comparable to those from fog room curing. The influence of high temperature at the early ages of hardening is more pronounced than that of OPC concrete. However this advantage at the very early stage like in OPC concrete is usually achieved at the expense of long term strength potential and the 28 days strengths are considerably lower than that cured under normal condition. The modulus of elasticity of RHA concrete is found to be lower than that of OPC concrete under all curing conditions investigated in this study. |
| Year | 1985 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul |
| Examination Committee(s) | Brotton, Derick M. ;Pama, Ricardo P. |
| Scholarship Donor(s) | Royal Norwegian Government; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1985 |